PVP/FeC6H5O7 composite nanofibers were prepared via electrospinning method. After 3 h of calcinations, the composite PVP/FeC6H5O7 nanofibers were turned to gamma-Fe2O3 nanofibers. X-ray diffraction (XRD), scanning electron microscopy(SEM) and the Brunauer-Emmett-Teller(BET) method were employed to characterize the products. Before calcinations, the composite nanofibers had smooth and uniform surfaces with an average diameter about 1000 nm. After calcinations, the nanofibers shrank but maintained the continuous structures with an average diameter about 600 nm. When used to detect acetone, sensor based on gamma-Fe2O3 nanofibers exhibited high response, good linear dependence (7.88 x 10(2)-1.58 x10(5) mg/m(3)), fast response and recovery speed at 230 degrees C. The sensor also showed good stability. These properties make the gamma-Fe2O3 nanofibers good candidates for acetone detection.